I don't think the Customs from 2005 had a long tenon, but easy enough to pull a neck pickup and verify. Pickups were 490R and 498T if memory serves. Almost every Les Paul post 1982 has SOME weight relief. Usually the 9 hole weight relief pattern. Value depends a lot on condition. I've seen them anywhere from $1600 for one with non original pickups and a headstock break to people trying to get more than $3k for really good condition. Just depends on what condition you're looking for and how patient you are, but there are deals out there.
Condition is key, White is at a premium. I bought one a year ago after looking since the 80's...they are always priced on the high side of the Les Paul market...Not long tenon ( I think) I always popped a pick up if I wanted to know....factory case is a plus, any paperwork, I think 05 is a good year but like all Pauls there are good and bad...weight makes a difference to a lot of players, Customs especially...under10 lbs are a faster movers and preferred by most. If you like it buy it. In my experience there is never a good deal on good white customs. They have been expensive my whole life. YMMV